Today, many manufactured products in the automotive, aerospace, wind energy, marine vessel, and defense technologies may include structures fabricated from multilayer composite materials. When properly designed and fabricated, multilayer composite structures can outperform structures fabricated by conventional methods, e.g., by bending, machining, and fastening pieces, or by milling a structure from a single material. A multilayer composite structure can provide superior durability and strength-to-weight ratio over structures fabricated by conventional methods. Composite structures can provide additional benefits over traditional structures depending on the particular application, because composite structures can be tailored to meet specific demands of a particular application.
Designing and fabricating a structure comprising multiple layers of composite material may pose engineering challenges. Current computer-aided design (CAD) tools are well adapted for providing dimensional data to aid in traditional design and manufacture of structures, e.g., providing renderings with dimensional data to guide the milling of a piece. However, CAD tools are not well adapted for providing data to guide the fabrication of a structure from multiple layers of composite material.
Add-on tools have been developed to extend the capabilities of CAD tools, so that they may be used for designing composite structures. Vistagy, Inc. of Waltham, Mass. provides several add-on tools, such as the product FiberSIM®, which can add fiber-composite multilayer design functionality to CAD software packages. Such add-on tools have been used in conjunction with the CAD tools by design engineers to facilitate development of a conceived multilayer structure into a commercial product. However, even with such tools, the design of multilayer composite structures can be difficult and computationally intensive. Typically, it is not known beforehand how large each layer should be and how layers of different sizes should be distributed within the structure's volume. Often, layers are distributed in successive trial-and-error layouts, with data being recalculated for each trial. Numerous iterations may be required before an acceptable distribution of layers is identified.